code: def __getitem__(self, key):
      if key in self.convention:
          return self.convention[key](self.const, self.table)
      elif hasattr(self, "_key_%s" % key):
          return getattr(self, "_key_%s" % key)()
      else:
          col_template = re.match(r".*_?column_(\d+)(_?N)?_.+", key)
          if col_template:
              idx = col_template.group(1)
              multiples = col_template.group(2)
  
              if multiples:
                  if self._is_fk:
                      elems = self.const.elements
                  else:
                      elems = list(self.const.columns)
                  tokens = []
                  for idx, elem in enumerate(elems):
                      attr = "_key_" + key.replace("0" + multiples, "X")
                      try:
                          tokens.append(getattr(self, attr)(idx))
                      except AttributeError:
                          raise KeyError(key)
                  sep = "_" if multiples.startswith("_") else ""
                  return sep.join(tokens)
              else:
                  attr = "_key_" + key.replace(idx, "X")
                  idx = int(idx)
                  if hasattr(self, attr):
                      return getattr(self, attr)(idx)
      raise KeyError(key)
  
imports: from __future__ import annotations
  import re
  from .None import events
  from .base import _NONE_NAME
  from .elements import conv
  from .schema import CheckConstraint
  from .schema import Column
  from .schema import Constraint
  from .schema import ForeignKeyConstraint
  from .schema import Index
  from .schema import PrimaryKeyConstraint
  from .schema import Table
  from .schema import UniqueConstraint
  from ..None import event
  from ..None import exc
label_desc: Use image node_id 10 for calling the ConventionDict obj's underlying member method code with example usage: obj.__getitem__(key) and returns: self, getattr, sep, getattr